A company has multiple VPCs across AWS Regions to support workloads that are isolated from workloads in other Regions. A new requirement mandates that the company’s VPCs must be able to communicate with all other VPCs across all Regions. Which solution will meet these requirements with the LEAST amount of administrative effort?

AWS Transit Gateway simplifies network architecture by acting as a central hub for VPCs and on-premises networks. For this scenario, Transit Gateway allows all VPCs within a Region to communicate with each other through a single connection to the Transit Gateway, significantly reducing the number of peering connections needed compared to a full mesh of VPC peering. To enable cross-Region communication, Transit Gateway peering connects Transit Gateways in different Regions, allowing VPCs attached to one Transit Gateway to communicate with VPCs attached to another. This solution minimizes administrative overhead because you manage a central Transit Gateway in each Region and then peer those Transit Gateways, rather than managing a large number of individual VPC peering connections. VPC peering requires a separate connection for every pair of VPCs, which becomes administratively complex and difficult to scale with many VPCs across multiple Regions. AWS Direct Connect gateways are primarily for connecting on-premises networks to multiple VPCs in different Regions, not for inter-VPC communication within or across Regions. AWS PrivateLink is designed for secure, private connectivity between services hosted in different VPCs or accounts, not for general-purpose inter-VPC communication across an entire network.